package org.bouncycastle.asn1;

import java.io.IOException;

import org.bouncycastle.util.Strings;

/**
 * DER UTF8String object.
 */
public class DERUTF8String extends ASN1Object implements DERString {
    String string;

    /**
     * return an UTF8 string from the passed in object.
     * 
     * @exception IllegalArgumentException
     *                if the object cannot be converted.
     */
    public static DERUTF8String getInstance(Object obj) {
        if (obj == null || obj instanceof DERUTF8String) {
            return (DERUTF8String) obj;
        }

        throw new IllegalArgumentException("illegal object in getInstance: "
                + obj.getClass().getName());
    }

    /**
     * return an UTF8 String from a tagged object.
     * 
     * @param obj
     *            the tagged object holding the object we want
     * @param explicit
     *            true if the object is meant to be explicitly tagged false
     *            otherwise.
     * @exception IllegalArgumentException
     *                if the tagged object cannot be converted.
     */
    public static DERUTF8String getInstance(ASN1TaggedObject obj,
            boolean explicit) {
        DERObject o = obj.getObject();

        if (explicit || o instanceof DERUTF8String) {
            return getInstance(o);
        } else {
            return new DERUTF8String(ASN1OctetString.getInstance(o).getOctets());
        }
    }

    /**
     * basic constructor - byte encoded string.
     */
    public DERUTF8String(byte[] string) {
        try {
            this.string = Strings.fromUTF8ByteArray(string);
        } catch (ArrayIndexOutOfBoundsException e) {
            throw new IllegalArgumentException("UTF8 encoding invalid");
        }
    }

    /**
     * basic constructor
     */
    public DERUTF8String(String string) {
        this.string = string;
    }

    public String getString() {
        return string;
    }

    public String toString() {
        return string;
    }

    public int hashCode() {
        return this.getString().hashCode();
    }

    boolean asn1Equals(DERObject o) {
        if (!(o instanceof DERUTF8String)) {
            return false;
        }

        DERUTF8String s = (DERUTF8String) o;

        return this.getString().equals(s.getString());
    }

    void encode(DEROutputStream out) throws IOException {
        out.writeEncoded(UTF8_STRING, Strings.toUTF8ByteArray(string));
    }
}
